The popularity of down is a testimony to its effectiveness, even as it remains one of the more expensive outerwear options. Other than cost, about the only downside to down is you can’t get it wet. Wet down collapses into hard-to-dry clumps, limiting both its insulating ability and usefulness in wet environments. Some down is treated (it’s called ‘hydrophobic down’) to resist water, and of course a water and wind-resistant shell material will help. Here are three things to think about when choosing a down jacket:

Top Pick

Zipped pockets on the arms give you space to carry smaller essentials, and an elastic-bound hem at the waist helps retain heat. Eddie Bauer

The quality of the down is determined by its loft and insulating ability, and is measured numerically as ‘fill power.’ A higher fill power (800—900) means the down holds its loft (and insulating air) better than a down with a lower rating. It’s also more expensive. Keep in mind that the quality of the down is important, but so is the amount of down used in the jacket. You should also check to see if the fill is 100 percent down.

Head Protection

A good down jacket is warm and versatile. The North Face

The more down used in the jacket, the warmer you will be. The higher the fill power rating the warmer you will be with the same quantity of down. In addition, down treated for water resistance (hydrophobic down) will also keep you warmer because it is slower to lose its insulating value when wet from either sweat or the rain.

High Style

Baffling the insulation tubes in the coat’s construction should overlap to eliminate cold spots. Tommy Hilfiger

The fabric used in the jacket will affect the garment’s resistance to wind and precipitation, as well as its breathability and packability. Gore-tex or a similar breathable yet waterproof fabric is a popular choice, but will weigh more and be less packable.

The construction matters not only for fit and wearing comfort, but for distributing the down to most effectively employ its insulating qualities. Look for baffling that overlaps layers of down and eliminates cold spots.